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Quantitative rates of brain glucose metabolism distinguish minimally conscious from vegetative state patients

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      The differentiation of the vegetative or unresponsive wakefulness syndrome (VS/UWS) from the minimally conscious state (MCS) is an important clinical issue. The cerebral metabolic rate of glucose (CMRglc) declines when consciousness is lost, and may reveal the residual cognitive function of these patients. However, no quantitative comparisons of cerebral glucose metabolism in VS/UWS and MCS have yet been reported. We calculated the regional and whole-brain CMRglc of 41 patients in the states of VS/UWS (n=14), MCS (n=21) or emergence from MCS (EMCS, n=6), and healthy volunteers (n=29). Global cortical CMRglc in VS/UWS and MCS averaged 42% and 55% of normal, respectively. Differences between VS/UWS and MCS were most pronounced in the frontoparietal cortex, at 42% and 60% of normal. In brainstem and thalamus, metabolism declined equally in the two conditions. In EMCS, metabolic rates were indistinguishable from those of MCS. Ordinal logistic regression predicted that patients are likely to emerge into MCS at CMRglc above 45% of normal. Receiver-operating characteristics showed that patients in MCS and VS/UWS can be differentiated with 82% accuracy, based on cortical metabolism. Together these results reveal a significant correlation between whole-brain energy metabolism and level of consciousness, suggesting that quantitative values of CMRglc reveal consciousness in severely brain-injured patients.

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            Author and article information

            [1 ]Department of Neuroscience and Pharmacology, University of Copenhagen , Copenhagen, Denmark
            [2 ]Cyclotron Research Centre and Neurology Department, University and University Hospital of Liège , Liège, Belgium
            [3 ]Department of Nuclear Medicine and PET Centre, Aarhus University Hospital , Aarhus, Denmark
            [4 ]Centre for Advanced Imaging, University of Queensland , Brisbane, Australia
            [5 ]Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Harvard Medical School , Boston, Massachusetts, USA
            [6 ]Department of Biomedicine—Pharmacology, Aarhus University , Aarhus, Denmark
            [7 ]Department of Nuclear Medicine, University Hospital of Liège , Liège, Belgium
            [8 ]Department of Neurology, McGill University , Montréal, Québec, Canada
            [9 ]Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions , Baltimore, Maryland, USA
            Author notes
            [* ]Department of Neuroscience and Pharmacology, Panum Institute , Blegdamsvej 3, Copenhagen N 220, Denmark. E-mail: Gjedde@

            These authors contributed equally to the work.

            J Cereb Blood Flow Metab
            J. Cereb. Blood Flow Metab
            Journal of Cerebral Blood Flow & Metabolism
            Nature Publishing Group
            January 2015
            08 October 2014
            1 January 2015
            : 35
            : 1
            : 58-65
            Copyright © 2015 International Society for Cerebral Blood Flow & Metabolism, Inc.

            This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. To view a copy of this license, visit

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